1. Field of the Disclosure
The present disclosure relates to organic anti-reflective coating compositions and methods for forming photoresist patterns using the same. More particularly, the present disclosure relates to organic anti-reflective coating compositions comprising organo-silicon based polymers and methods for forming photoresist patterns using the same.
2. Description of the Related Art
Standing waves are often generated during microfine photoresist pattern-forming processes and conventional semiconductor production methods. Standing waves are generated because of the optical properties of a lower film layer (such as, for example, the substrate of a photoresist film) and/or because the thickness of the photoresist film is not uniform (i.e., it is varied). Standing waves derived from light diffracted and/or reflected from the substrate cause reflective notching and/or varying of the critical dimension (hereinafter referred to as “CD”) of the photoresist pattern. Accordingly, layers which prevent light from reflecting off of the substrate have been introduced between the substrate and the photoresist. Such layers are called anti-reflective films, and typically comprise materials having a high quality light-absorbing ability within a wavelength range of an exposure light source. Anti-reflective films may generally be classified into inorganic and organic based anti-reflective films.
Organic anti-reflective films have been widely used in microfine photoresist pattern-forming processes. Organic anti-reflective films typically possess the following properties:
(1) After the anti-reflective film is formed and while a photoresist comprising a photosensitive material is coated or otherwise applied onto the anti-reflective film, the anti-reflective film should not dissolve (i.e., it is not soluble) in the photoresist solvent. For this reason, organic anti-reflective films generally have cross-linked structures (which are generated by conducting a baking process). Such cross-linked structures also inhibit the generation of undesirable chemical by-products;
(2) In order to prevent the scattered reflection of light from the substrate, the film contains certain materials to absorb light within a wavelength range of an exposure light source; and,
(3) The anti-reflective coating composition includes a particular catalyst to activate the cross-linking reaction.
Thus, conventional organic anti-reflective coating compositions generally comprise a cross-linking agent for generating the desired cross-linked anti-reflective film structure, a light-absorbing agent for absorbing light within a wavelength range of an exposure light source, and a thermal acid generator as a catalyst for activating the cross-linking reaction.
Although anti-reflective films preferably have a high absorbance for absorbing light and inhibiting the reflection of light from the substrate as described above, the absorbance is not always directly proportionate to the reflectance. On the contrary, excessively high light absorbance may cause the amount of light which penetrates through the anti-reflective film to decrease and lead to an increase in the reflectance of the anti-reflective film such that it may be difficult to efficiently reduce the standing waves and obtain a quality photoresist pattern. Thus, the absorbance of organic anti-reflective films preferably ranges between about 0.3 and about 0.6.
Most organic materials generally contained in conventional organic anti-reflective coating compositions have an absorbance of more than 0.7 with respect to a 157 nm F2 light source. Accordingly, organic anti-reflective films formed from such compositions show excessively high absorbance with respect to the 157 nm light source and, in the case of a microfine pattern-forming process using a 157 nm F2 light source, the standing waves cannot be reduced such that quality photoresist patterns can be obtained.
Due to the problems of existing organic anti-reflective compositions noted above, improved organic anti-reflective coating compositions are needed to efficiently remove standing waves and for providing stable photoresist patterns.